I. Field
The present disclosure relates generally to communication, and more specifically to techniques for transmitting and receiving data in a wireless communication system.
II. Background
In a wireless communication system, a transmitter may utilize multiple (T) transmit antennas for data transmission to a receiver equipped with multiple (R) receive antennas. The multiple transmit and receive antennas form a multiple-input multiple-output (MIMO) channel that may be used to increase throughput and/or improve reliability. For example, the transmitter may transmit up to T symbol streams simultaneously from the T transmit antennas to improve throughput. Alternatively, the transmitter may transmit a single symbol stream from all T transmit antennas to improve reception by the receiver.
To achieve good performance, the receiver may estimate the MIMO channel response and determine a precoding matrix to use for a MIMO transmission. The receiver may also determine a channel quality indicator (CQI) or a modulation and coding scheme (MCS) for each symbol stream sent in the MIMO transmission. The receiver may send feedback information to the transmitter. This feedback information may include the precoding matrix as well as the CQI or MCS for each symbol stream. The feedback information is useful to the transmitter but represents overhead. It is desirable to reduce the amount of feedback information to send for the MIMO transmission.